Nature's spring: Cod bounce back

The BBC article by Richard Black references the recent Nature paper Transient dynamics of an altered large marine ecosystem (subscription or payment required) that explores the dynamics of Atlantic cod stocks after the near extinction in the early 1990s and the subsequent cod fishing moratorium.  The paper suggests that stocks of predatory fish (cod, haddock and saithe/pollock) were slow to recover due to the complex interactions and feedback loops of the marine ecosystem. 

Overfishing of top predators resulted in an explosion of forage fish (herring, capelin and sand lance) that fed on the eggs and larvae of the predatory species.  The forage species also affected zooplanton, the lowest level of the food chain, resulting in a dramatic oscillation of forage fish stocks.  Predatory fish were able to slowly rebuild during periods when forage fish stocks were low.  Recovery of the ecosystem involved many more factors than stopping overfishing. 

Understanding Complex Situations - a Fish Story explores the implications of dealing with complex systems.


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